It's not a fair comparison.

Despite my nickname, I'm more of a masher than a spiner, because our fixed gear are geared for *normal* street use, not top velocity, I simply cannot keep with roadies (have tried) because I fatigue too quickly trying to spin 48x16, not too bad but not high enough to spin along w intermediate/advanced roadies.
Having said that, on a long uninterrupted 20 miles flat stretch I can gain few mins on my geared bike, which in terms of commuting is nothing but is a lifetime in racing, depending how you see it.